The present invention is directed to a cutting insert. More particularly, the present invention is directed to a titanium carbonitride-based cermet cutting insert (hereinafter referred to as "TiCN"), which exhibits superior wear resistance and toughness. Such a cutting insert is also longer lasting and resistant to damage such as chipping and breaking of the cutting edge while in continuous and discontinuous use.
In recent years, a demand for factory automation has created a need for longer lasting cutting inserts which are tough and wear resistant.
In an attempt to fulfill this demand for superior cutting inserts, Japanese Laid Open Patent Publication No 62-170452 and 63-83241 proposes a TiCN-based cermet cutting insert which essentially contains from about 5 to about 30 vol% of a binding phase, which is mainly composed of one of Co and Ni, with the balance consisting of a hard dispersion phase.
The hard dispersion phase includes a duplex and/or a triplex structure with a core formed of a carbonitride solid solution of Ti and one of a V, Hf, Cr, Ta, Nb, Zr, W and Mo (hereinafter referred to as ("Ti,M)CN").
However, these prior art TiCN-based cermet cutting inserts have been unable to fulfill the abovementioned demand because of their inability to withstand the demands of continuously cutting steel in an industrial setting. Notwithstanding the toughness of these prior art cutting inserts, such cutting inserts are prone to extensive breakage and chipping of their cutting edges while in continuous use.
In order to overcome the aboveintentioned drawback associated with the use of prior art TiCN-based cermet cutting inserts in an industrial setting, the present invention aims at providing a TiCN-based cermet cutting insert which exhibits superior toughness and wear resistance. Additionally, the TiCN-based cermet cutting insert of the present invention aims at increasing the life of the cutting insert, and substantially improving its resistance to chipping and breaking of the cutting edge while continuously cutting steel.